I would think it would depend on what the "just in case" is you were stashing it for. A lot of the emergency prep stuff recommends having a 72 hour kit, so I'd think that at least 72 hours would be a good amount, but I haven't pumped at all for this baby, and never pumped with the last baby either so I don't have experience actually storing it myself.

__________________ Mama to Lily 5/2010 and Joseph 7/2011 and Wife to Chris

I am freezing as much as I can just in case. I'm not going crazy pumping but once a day I get an extra couple ounces after feeding and save it. I know someone who froze enough to stop breastfeeding and continue giving breast milk via bottle for a few months.

I had two weeks built up and I was trying for more, but when I went back to work my supply dropped considerably. Now I have two bottle stored and I have to pump like crazy all weekend for any additional time away from my LO.